(1) Field of the Invention
The present invention relates to an apparatus for preventing an error operation during a withdrawal of a part, in particular during maintenance of an electronic apparatus while the apparatus is active.
(2) Description of the Related Art
The recent improvements in the reliability of electronic apparatus such as electronic computer systems have been accompanied by a requirement for maintenance of the apparatus while it is active. Maintenance carried out while the apparatus is active entails withdrawing only a defective part while the apparatus is supplied with electric power.
Many electronic apparatuses are designed to allow maintenance while the apparatus is active, by providing a duplex system of the parts composing the electronic apparatus. This, however, inevitably greatly increases the number of the parts composing the electronic apparatus and further, leads to an increase in the number of maintenance engineers, such as customer engineers (CE), required. In view of this situation, it is important to prevent a system down state of the electronic apparatus due to an error operation caused by withdrawing a functioning part from the electronic apparatus while exchanging a functioning part for a defective part.
Conventionally, a lamp on a defective part is lit, or information that a part is defective is displayed at a display screen, to warn an operator that a part is defective.
These methods have drawbacks, however, in that when a lamp is lit indicating a defective part, it is impossible to prevent a burnout of the lamp due to an end of its operational life, etc., and therefore, a functioning part may be withdrawn in error from the panel of the electronic apparatus.
When displaying information on the display screen, the operator may misread the displayed information, and in such a case also, a functioning part may be erroneously withdrawn from the panel of the electronic apparatus.
If a functioning part is erroneously withdrawn from the panel, the electronic apparatus may be brought to a system down condition.